TL1A is a newly discovered signal molecule that may be crucially involved in the maintenance of chronic inflammatory disorders. TL1A has also been demonstrated in psoriatic skin but the importance of TL1A in psoriasis is still unknown. Understanding inflammatory signal molecules in psoriasis is important because the development of new drugs directed against relevant signal molecules (e.g. TNF-α and IL12/23) has proved to be a very efficacious treatment principle. However, despite the dramatic progress in therapeutic options during the last decade, there is still a fraction of patients that are insufficiently treated with the currently available therapies. TL1A has been claimed to be the next important target for development of biologics in the field of chronic inflammation.